Organelles of the Cell (updated)

so the topic of this video are the many organelles found within cells there's a lot to talk about so let's get started first really just a question to punch you know what parts do cells possess that help them survive pause the video think about it for a moment i'm going to go ahead and proceed okay so first of all you know cells need to take in food rid ways to reproduce and as a result they need to have a variety of parts that helps them perform their job and there's really three main sections within the cell the cell membrane of the plasma membrane being the outer boundary the nucleus it's pulsing right there in the picture so we're talking about eukaryotes in this video and third being the liquidy interior the cytoplasm so let's talk about that first the cytoplasm so let's start with the cytoplasm the jelly-like material inside of the cell and it's in the cytoplasm that most organelles are suspended within the nucleus ribosomes vacuoles mitochondria chloroplasts endoplasmic reticulum the golgi body lysosomes this is a list here of some of the organelles that are suspended within the cytoplasm so underneath the microscope you can actually see what is known as cytoplasmic streaming in this case those green circles moving around in the cell those are chloroplasts and they're floating in the cell they're floating in the cells cytoplasm and underneath the microscope you can sometimes see this but what does the cytoplasm really do number one because it's made mostly from water it helps to dissolve solutes you know you might know that water is a solvent and so things will dissolve and break apart when in water and so solutes like proteins and carbohydrates they can dissolve with the help of chemical reactions in the cytoplasm and another function is to help move materials around so the cytoplasm actually plays a vital role within the life of a cell let's move on next to the plasma membrane also known as the cell membrane and first of all let's talk about its composition what it's made from first of all you can see a phospholipid bilayer two layers of lipids one right one on top of the other right now and embedded within the plasma membrane here's a protein channel there are carbohydrates on the outside of the of the membrane and embedded within our cholesterol molecules to add flexibility and so the job of the plasma membrane is really to allow certain materials to pass and restrict the passage of others notice carbon dioxide and oxygen are easily passing through the phospholipid bilayer but the plasma membrane is semi-permeable because only certain molecules can do this here's glucose c6h12o6 it's just physically too big to slip through the phospholipid bilayer but our cells need glucose inside so glucose can actually enter through the protein channel that you just saw in the animation so there's a variety of ways in which the cell membrane can bring in materials and restrict others well here is uh the the nucleus flashing in the black box let's zoom on and when we zoom into the nucleus for a closer look uh let's talk about the job you know what you're often told in middle school is that it's the headquarters of the cell it controls the cell's activity but how does it do that well it's because of what's inside the nucleus there are strands of dna called chromatin long strands of dna loose linear versions of dna and you might know that dna contains the active instructions to make a protein so chromatin is the active form of dna where it's actively being used to make proteins and this is why we say the nucleus controls the cell's activity because the dna is used to make proteins and the proteins function in a variety of ways to keep our cells going you can also notice that there's a big spot inside of the nucleus labeled the nucleolus we're going to see what its job is is to make something called ribosomes and that's going to be important in a little bit and in this picture here an electron microscope picture you can see that's the nucleus right there and you can see the dark spot that's the nucleolus and the nucleolus again creates ribosomes and sends out the ribosomes and you'll see what the ribosomes do in just a moment well let's go ahead and move on to the endoplasmic reticulum and in the flashing box you can see there's two of them there's a rough and a smooth er let's zoom in and let's go ahead and talk about the rough er first notice in the picture here that it's covered in dots circles labeled ribosomes and the ribosomes were crea or were created in the nucleus by the nucleolus and in this picture here you can see there's the nucleus there's the nucleolus and there's the rough er now look at the nucleolus it's making some black circles those are the ribosomes and the ribosomes are being sent into the rough er and the rough er is really like a a network of tubes and tunnels and the function of the rough er has helped transport these ribosomes now you're kind of seeing what the job of a ribosome is is they make proteins so the rough er's job is to transport the protein making ribosomes around the cell and so a common analogy is that the rough er is kind of like a subway you know the people inside the subway would be like the rough er they're being transported around a city and in this case the ribosomes are being transported around a cell and so if we look at the other endoplasmic reticulum the smooth first of all it's called smooth because if you notice in the picture there's no dots on it there's no ribosomes so the rough er is covered in ribosomes and underneath the microscope kind of has a rough textured appearance but the smooth er is not covered in ribosomes and so would uh you know reason to believe it would be a smooth texture and so the job of the rough i'm sorry the job of the smooth er is to help create fats and break down many of the toxins that may enter into a cell so really important in the overall life of the cell okay so let's talk about those ribosomes we said they're created by the nucleolus and there they are in the nucleolus being created and they are they will travel and be transported through the rough er and that's what we see happening in the blue area but what do they actually do their job is to make proteins let's explore that in a little more detail so here's a ribosome you might know that a protein is made from a collection of amino acids and so there's a process that the ribosome performs called translation and in this process amino acids are gathered one at a time and they're linked together and so that's the job of the ribosome is to gather these building blocks called amino acids link them together and when you link them all together you make what's called a polypeptide now you might remember from another topic that polypeptides will twist and fold and wrap into a final thing called a protein but that's the job of a ribosome is to build proteins and that protein has a function somewhere within the organism okay let's zoom in to the golgi body next and when we do there's the nucleus there's the nucleolus the rough er and in green there's the golgi body now what we're going to do is we're going to zoom into the rough er and you can see there's the rough er and all the gray circles those are ribosomes and like we just said ribosomes will make a protein and there's a protein p-r-o-t-e-i-n but this protein is not quite finished it's an immature protein and so what happens is a piece of the rough er will actually enclose and pinch off and enclose the protein forming what's called a vesicle a protective organelle and this organelle will carry the immature protein towards the golgi body so here's the golgi body and here comes that vesicle carrying the immature protein the protein will now be modified and altered and finalized and become a mature protein as it works its way through the golgi body and then a membrane from the golgi body will and i will enclose around the protein forming another vesicle and this protective vesicle will protect this finished protein as it exits towards the cell membrane and here's the cell membrane here comes the vesicle it fuses and the protein is released to the outside of the cell and can be used as needed by the organism so if you notice a little assembly line process the nucleolus makes ribosomes the ribosomes move along the rough er the golgi body sorts packages the proteins and then a vesicle will release the protein from the cell okay so let's do a little bit of review pause the video and try to answer these seven questions i'm going to go over the answers right now number one which organelle builds proteins i hope you said ribosomes number two which organelle stores dna well that's the nucleus number three which produces ribosomes that's the nucleolus number four which creates fats and breaks down toxins that's the smooth er number five which packages and releases proteins from a cell that's the golgi body number six which allows material to enter or exit a cell that's the cell membrane of the plasma membrane and number seven which links chains of amino acids together that's also a ribosome number one and number seven it's the same question just worded differently so here's another review challenge place these four steps in order from start to finish pause the video because i'm going to go over the answers in three two one okay so i hope you thought that step c was first the nucleolus makes ribosomes and then d the ribosomes exit the nucleus and then b the ribosomes travel along the rough er and create proteins and then a the golgi body packages and exports the finished proteins in a vesicle so we come to the mitochondria let's zoom in and here's a picture of the mitochondria and here's an actual microscopic picture right here you know in middle school they tell you that your middle school teacher probably tells you the mitochondria it's the powerhouse of the cell because it makes energy what do we mean by that well the job of the mitochondria yes is to make energy but what it does is it performs a process called cellular respiration to create a molecule an energy rich molecule called atp adenosine triphosphate let's talk about this so here is the chemical equation of cellular respiration now if you've never seen a chemical equation before there are some molecules on the left of an arrow we call these the reactants so in cellular respiration glucose c6h12o6 and oxygen are the reactants they go into the mitochondria and then in blue here on the on the right side of the arrow of a chemical equation these are what are called the products in other words what's created what's produced and out of the mitochondria comes carbon dioxide and water and molecules of atp now atp the reason they're flashing right here because this is why your middle school teachers tell you that the mitochondria is the powerhouse the mitochondria creates this molecule called atp adenosine triphosphate another day we'll talk about how it's so full of energy so kind of a interesting uh side note here on the mitochondria it's involved in the endosymbiosis theory and so the mitochondria were once thought to be a free living prokaryotic organism and the reason we think that is it has a lot of qualities of of a living thing they have their own dna their own ribosomes they make their own proteins they can replicate this thing almost acts like it's still alive although today it's not a living organelle sorry it's not a living organism it's a part of a cell it's an organelle and so the way we think it happened is a larger cell swallowed up the mitochondrial ancestor and the mitochondrial ancestor survived and kept multiplying and reproducing it's just trapped inside of the larger cell that that swallowed it and over time the largest cell multiplies and divides into two and you know you repeat this process and over time they both become become completely dependent on one another and if you ask yourself well what advantage would the larger cell have with mitochondria living inside of it the ability to make energy to make that molecule called atp that's a big advantage if you can make your own energy you have a survival advantage and then ask yourself well if you're what advantage would the mitochondria have living inside of the larger cell well you'd have a home and protection from other organisms so over time they've both become completely dependent on one another and this is known as the theory of endosymbiosis okay let's move on to the lysosomes and if we zoom on in here's a cell with a lysosome and there's little animated scissors inside of the lysosome these are symbolic of the digestive enzymes found within a lysosome and so the job of a lysosome is to one break down food so here's a protein so let's say that this protein is uh swallowed up by the cell and it goes into our lysosome or that protein will be broken down into the individual units or the amino acids and then those amino acids can be used by the cell in a variety of ways well let's pretend that the cell is a white blood cell another job of the lysosome is to kill pathogens you know pathogen is just the word for a foreign disease causing you know microorganisms like a virus or a bacteria and so in this case a virus has landed on a white blood cell a little pocket begins to form and the cell actually wraps around and completely swallows the virus this is the process known as phagocytosis where a cell will swallow a large object through the cell membrane that virus is then placed inside of a lysosome where the digestive enzymes will destroy it so lysosomes are very important in our immune system's ability to rid ourselves of infection and a third process uh that the lysosome performs is a process known as autolysis or autolysis that uh and where it will actually the lysosomes will actually destroy a dying cell let's pretend this cell right here is an aging dying cell the lysosomes will release their their animated scissors here their digestive enzymes and this dying cell will be destroyed and then a healthy neighbor can multiply make a copy of itself and kind of fill that space to help the overall organism continue to survive so very important organelle the lysosome okay in the black box here we have the centrioles let's go ahead and zoom on into centrioles these are in animal cells only and so if we zoom out into centrioles we can see that they are cylinder shaped uh it's a cylinder-shaped organelle made from proteins known as microtubules and the job of the centrioles is to help separate dna to opposite ends of the cell when they divide when cells do a process known as mitosis so let's watch what centrioles do here's a cell that's about to divide watch the dna in the middle cells will copy their dna and then the centrioles will duplicate themselves the centrioles then move to opposite ends of the cell and little protein fibers called spindle fibers grow out from the centrioles and attach themselves to the dna of the cell and then the spindle fibers begin to pull the dna to opposite ends of the cell and eventually once the dna is pulled to opposite ends then the cell begins to pinch inward and ultimately there are two cells so the centrioles play a really important role in separating the dna of a dividing cell during mitosis okay so let's now talk about the cytoskeleton and in this picture you can see in a variety of locations there are these little fibers these little threads uh that are all throughout the cell and these are the cytoskeleton a network of protein fibers that crisscross the cell and the job of the cytoskeleton is number one to help give the cell some shape they it adds internal support you know much like the framing of a house adds support internally inside the walls of a house and in this picture here there are three cells and this is a great picture the three cells in the blue area shows the cell's nucleus the green area shows all the mitochondria and the red area shows the cytoskeleton and you can see how the red fibers criss-cross throughout the inside of the cell to help give these cells shape and internal support okay so another function of the cytoskeleton well first of all here's the cell membrane that we talked about earlier and notice the cytoskeleton also provides tracts for molecules to move along so molecules will move along the tracks of the cytoskeleton as they enter or as they exit a cell and move around within the cell kind of a fun thing to google and look around are these fun little proteins called motor proteins because they're proteins but but they actually look like they walk along the cytoskeleton and they usually carry food molecules organelles or any other molecules that the cell might need but what these motor proteins are walking along are the tracks of the cytoskeleton so a very important function is help molecule movement all right let's do two organelles on one slide here the cilia and the flagella they both have a same a similar function if cells are capable of movement it's because of the actions of either cilia or flagella so let's talk about cilia first let's zoom on in and you can see these little hairs let's zoom in even closer and you can see that these cilia are little tiny short hair like extensions they're incredibly numerous way too many to count there's no way to ever be able to count them there's just so many of them on one cell and and they wiggle back and forth and helps the cell propel itself through its liquidy into uh its liquidy environment that it might be living in so here's a picture of a microscopic organism this one the cilia uh will actually beat in a rhythmic circular manner to draw a food inside of it and so even though the the cell doesn't swim around this cell is anchored into place it uses its cilia to kind of create a current to bring in uh you know molecules for it to eat so let's look at the flagella next well first of all in this picture here's an egg cell and here's a sperm cell notice the sperm cell has a long tail that's called the flagellum which is singular flagella being plural so the flagella or flagellum is a long whip-like extension it whips back and forth and helps the cell swim now notice in this picture right here of e coli bacteria the the e coli actually have more than one flagellum some cells may only have one flagellum others may have more than one point is there's not that many of them compared to the cilia which are more numerous okay let's talk next about the cell wall outermost layer of plants fungus and bacteria cells now the cell wall of plants and fungus and bacteria are not the same the cell wall of plants is different from the cell wall of fungus the cell wall of fungus different from the cell wall of bacteria but these types of organisms do have what's called a cell wall let's talk about plants so here's a plant cell and in yellow is the cell membrane or the plasma membrane and in green is the cell wall and the job of the cell wall had support for growth so on a historical note about the cell wall it was first witnessed by robert hook in 1665 using the microscope that he that he created he sliced a real thin piece of cork and looked at it underneath the microscope and this is the picture that he drew right here and so he examined cork cells cork cells are dead the only thing that he could see was the outer boundary the cell wall and the reason the the cell wall still existed even though the cells are dead is because it's made from a very tough carbohydrate called cellulose but he named these boxes cells because they look like tiny rooms and another word for a tiny room would be a cell okay let's move on to the chloroplast next the job of the chloroplast perform photosynthesis well here are several dozen leaf cells let's zoom in and when we do we can see that you know this is one cell right here and inside there's dozens and dozens of chloroplasts these are the organelles that perform photosynthesis and in this animation right here we see cytoplasmic streaming you can see the chloroplasts are the green circles that are floating around within these plant cells here and so here's a leaf and so this is another example of a chemical equation and as we said earlier the molecules listed on the left of the arrow these are the reactants so what goes into photosynthesis is on the left but the right side of the ear are called the products and that's what comes out of photosynthesis so in this case the reactants what goes into for instance leaf cells sunlight water carbon dioxide these are the reactants they go into the plant cells and on the right hand side of the arrow what comes out are the products in this case o2 is oxygen and glucose now glucose is the full purpose of photosynthesis the plants are trying to make glucose so they can feed themselves the oxygen is just a gaseous waste product and as we said earlier with the mitochondria the chloroplasts are also involved in the endosymbiosis theory the chloroplast like the mitochondria is believed to have once been a free living prokaryotic organism and for the same evidence that we said earlier with the mitochondria chloroplasts also have their own dna their own ribosomes they make their own proteins and they can replicate so they have many actions they perform many actions that lead us to believe that at one time they used to be alive today they're not they're organelles of plant cells but we believe that they were swallowed by a larger cell and they survived and and multiplied inside of the larger cell now the larger cell also would grow and eventually multiply into two two cells and then repeat this process and like the mitochondria over time the chloroplast and the larger cell just become dependent upon one another and so what advantage would the larger cell have with chloroplast living inside of it well if you have a part inside of you that produces food for you you have an advantage and that's what the chloroplast does is it produces food that the largest cell can take advantage of well what advantage would a chloroplast have living inside of the larger cell again a home and protection from others okay let's move on to the vacuole next so here's a plant cell and this was this is a plant cell's central vacuole now the job of a vacuole is to store food water waste color pigments also when filled it adds internal pressure helps to support the cell from the inside and so in this picture here notice how the vacuole is filled with with uh with water and as a result the leaves of the plant are are fully supported but in this picture the vacuole is shrunken because this cell is not receiving enough water and as a result the leaves of a plant may look wilted so you can kind of tell if a plant needs more water based on whether or not the leaves are supported or wilted and in a plant cell right here we have again what's called the central vacuole a large central vacuole stores food water waste color pigments you've seen this picture a couple times throughout this video here this is these are plant cells and the green circles are the chloroplasts moving around the edge of the plants up but my question to you is and by the way this is known as cytoplasmic streaming my question to you is why are the chloroplasts only moving along the outer edge of the plant cell well the reason is because there's a big central vacuole that takes up most of the internal space of the cell now you can't see it because it's filled with water but it's there and so for that reason the other organelles are often pushed to the outer edge outer boundary of this of the plant cell animal cells also have vacuoles they store food and water and waste and such the difference being that they're just smaller and more randomly scattered throughout the cytoplasm like you see in this picture right here and there you have it wow i know there's a lot of information that was just covered well here's a little practice quiz i hope you find it helpful if you're in my class i'm happy to check your answers so thanks for watching everyone i'll catch you on the next one

Channel: Beverly Biology

Views: 2,280

Keywords: Organelles, Cells, Nucleus, Eukaryote, Mitochondria, Lysosome, endoplasmic, Golgi, Cell wall, plasma membrane, cytoplasm, cytoskeleton, centrioles, chloroplast, cilia, flagella

Id: A_wXDzT0yO0

Length: 28min 16sec (1696 seconds)

Published: Wed Jul 20 2022